B&W: Several companies. Foma, Ilford, Kodak and Fuji all make large format film, as does Efke.
Colour negative: Kodak and Fuji.
Colour positive (transparency): Fuji, and as of a few days ago, only in one film type - Velvia 100.

I have seen no evidence that suggests Velvia 50 and 100F is no longer available in 4x5 (or 8x10) in the US. All the sources that said it was discontinued a few days ago were UK sources. Until I see a source that says this is true for Fujifilm USA I don't believe it.